Two investigations of the visual motor capacity of primates are summarized: the role of the superior colliculus (SC) in the visual fixation necessary for clear vision and the activity of cerebral cortical area medial superior temporal (MST) neurons in the analysis of the optic flow stimuli generated as an observer moves through the environment. In work on the SC, cells in the anterior pole of the monkey SC have been shown to discharge vigorously during visual fixation and to pause during the generation of rapid or saccadic eye movements from one target in the field to another. This observation suggests that the fixation zone is acting to suppress the occurrence of saccades, making the activity of the fixation zone and the saccadic zone reciprocal. A test of this hypothesis was made by chemically inactivating the fixation zone and showing that the frequency of saccades to a visual target increased and that the latency of these saccades was very short. These observations support the hypothesis that the fixation activity in anterior SC suppresses the generation of saccadic eye movements as well as the notion that a separate system within the brain is necessary for visual fixation, just as other systems are necessary for saccadic and smooth pursuit eye movements. Analysis of MST neurons has shown that some cells responded to only one component of optic flow stimulation (eg, radial motion) while others responded to several components (eg, planar, circular, and radial motion). These neurons fell along a continuum of response ranging from those responsive to a single component of optic flow to those responsive triple-components. The organization of the visual receptive fields also varied along this continuum. The response to radial and circular motion could be explained on the basis of the planar sensitivity of the neuron in the case of triple- component neurons; such responsiveness to planar and circular motion was less likely to be the result of planar motion in the single-component neurons. These experiments indicate that the MST region of extrastriate cortex is capable of providing the analysis of the higher order motion of the optic flow stimulation encountered as the subject moves through the environment.